A brake system of this general type is known from EP A1-344 544.
The pump in the system described therein supplies fluid directly into the master cylinder. The result is that, during a control operation in which the pump delivery is switched on, the pressure fluid which does not flow via the flow control valve to the wheel brake is received by the master cylinder so that the pedal is pulsating in response to the control rhythm.
In order to prevent these pulsations, it is suggested to insert a non-return valve closing towards the master cylinder into the brake line between the point where the pressure line of the pump terminates and the master cylinder. Pressure fluid which cannot discharge by way of the flow control valve to the wheel brake is stored in a high-pressure accumulator.
So that pressure development can take place, a direct line between the wheel brake and the master cylinder is provided which contains a non-return valve opening towards the master cylinder.
Further, a high-pressure accumulator is provided which connects to the pressure side of the pump and can receive at least that quantity of pressure fluid which experiences pressure peaks.
The present invention provides a shut-off valve in a direct line between the pump and the master cylinder, which is opened when the high-pressure accumulator is filled. Preferably, a proportional pressure limiting valve can be provided as an outlet valve.